Throttle control device for internal-combustion engines



s. M. PARKER 2,657,776

THROTTLE CONTROL DEVICE FOR INTERNAL-COMBUSTION ENGINES Nov. 3, 1953 5Sheejs-Sheet l F'i led Sept. 17, 1951 5 Sheets-Sheet 2 Nov. 3, 1953 s.M. PARKER THROTTLE CONTROL DEVICE FOR INTERNAL-COMBUSTION ENGINES FiledSept. 17, 1951 3 s. M. PARKER ,776

THROTTLE CONTROL DEVICE FOR INTERNAL-COMBUSTION ENGINES Filed Sept. 17,1951 5 Sheets-Sheet 3 S. M. PARKER Nov.- 3, 1953 THROTTLE CONTROL DEVICEFOR INTERNAL-COMBUSTION ENGINES 5 Sheets-Sheet 4 Filed Sept. 17 1951 5.M. PARKER Nov. 3, 1953 THROTTLE CONTROL DEVICE FOR INTERNAL-COMBUSTIONENGINES 5 Sheets-Sheet 5 Filed Sept. 17, 1951 l. ullllfllllllilllfllPatented Nov. 3, 1953 THROTTLE CONTROL DEVICE FOR INTERNAL-COMBUSTIONENGINES Sydney Macdonald Parker, Leamington Spa, England, assignor toAutomotive Products Company Limited, Leamington Spa, England ApplicationSeptember 17, 1951, Serial No. 246,919

6 Claims.

This invention relates to throttle control devices for internalcombustion engines, and has for its object to provide a device,independent of the normal throttle control mechanism, which temporarilylimits to a predetermined range the possible setting of the throttle.The device is primarily intended to provide an appropriate setting ofthe throttle during the changing of gears in a variable-speed gear boxassociated with an engine, being operated for that purpose by the changespeed gear control.

According to the invention a throttle control device includes at leastone stop which is movable into its operative position to limit the rangeof movement of the throttle valve upon actuation of a control other thanthe normal throttle control, the said stop, in moving to its operativeposition, adjusting the throttle valve independently of the normalthrottle control if the position of the latter is such as to positionthe throttle valve at a, setting outside the limited range.

Further, according to the invention a throttle control device for theengine of a vehicle includes at least one stop which is movable into itsoperative position to limit the range of movement of the throttle valveupon operation of a change-speed gear control to disengage a gear andreturned to a position in which it does not obstruct movement of thethrottle valve through its full normal range when a gear is engaged, thesaid stop, in moving to its operative position, adjusting the throttlevalve independently of the normal throttle control if the position ofthe latter is such as to position the throttle valve at a settingoutside the limited range. v

The throttle valve is preferably positively con nected to a memberco-operating with the stop, and the normal throttle control mechanismacts on the said member through a resilient element so that the membercan move independently of such mechanism.

Two stops may be provided one of which, in its operative position,defines the upper limit of a range of movement of the throttle valve theother limit of which is the closed position of the said valve, whilstthe other, in its operative position, defines the lower limit of a rangeof movement of the throttle valve of which the other limit is themaximum normal throttle open- 2 tion, together with parts of agear-changing mechanism with the operation of which the throttle controldevice is associated;

Figure 2 is a detail view showing a pair of switches operated by thegear-changing mechanism of Figure 1;

Figure 3 is a side elevation of the throttle control device showndiagrammatically in Figure 1;

Figure 4 is a section on the line l4 of Figure 3;

Figure 5 is a plan view of the device shown in Figure 3;

Figure 6 is a diagram, similar to Figure 1, showing another form ofthrottle control device according to the invention, and parts of thegearchanging mechanism with which it is associated;

Figure '7 is a side elevation of the throttle control device showndiagrammatically in Figure 6;

Figure 8 is a sectional elevation of a vacuum control valve and itsoperating solenoids;

Figure 9 is a section on the line 9-9 of Figure 8;

Figures 10, 11 and 12 show a switch arrangement for operating thethrottle control device shown in Figure 6, Figure 9 being a side viewand. Figures 11 and 12 being sections on the lines Il-H and l2l2 ofFigure 10 respectively;

Figure 13 is a view of another switch mechanism for operating thethrottle control device shown in Figure 6, looking along the steeringcolumn of a vehicle to which the switch mechanism is attached;

Figure 14 is a section on the line l4l4 of Figure 13; and

Figure 15 is a view similar to Figure 7 showing a modification.

Referring to Figures 1 to 5 of the drawings, and more particularly toFigure 1, the throttle control device is shown at 20, and a liquidpressure operated gear-changing mechanism at 2|. The mechanism 2|operates a gear-box (not shown) of the well-known synchro-mesh typehaving four forward gears and reverse, through two links 22 and 23 whicheffect respectively the selection of the appropriate shift bar of thegear-box and the movement of the selected shift bar to engage the gear.The mechanism 2| comprises a double-acting liquid pressure cylinder 24in which is operable a piston 25 provided with cams with whichco-operate followers mounted on bell-crank levers pivoted to the links22 and 23. Liquid is supplied to the cylinder 24 from a suitablepressure source through a sliding plunger valve 26 of known type havinga followup action the valve being closed when its plunger is in anintermediate position, and being opened by movement of the plunger ineither direction, movement in one direction admitting liquid to one endof the cylinder and allowing it to escape from the other end, whilstmovement in the opposite direction admits liquidto the said other end ofthe cylinder, and allows liquid to escape from the said first end.

The valve 26 is operated through a rod 21 and floating lever 28 from ahand lever 29 movable in a quadrant 30, the floating lever 28 beingpivoted to a link 3| itself pivoted at one-end tora bell-crank lever 32carryinga. cam follower engaging a cam surface on the piston. 25, andcoupled at its other end to a return spring 33. The hand lever 29 movestowards'the left for downward gear changes, and towards the right forupward gear changes, the plunger of the valve 26 moving in the oppositedirection in each case, owing to the reversing action of thefloatinglever 28. 'The valve plunger extends right through the valve casing andcarries an abutment 34'co-opcrating with the operating plungers of twoelectric switches 35 and 35 (Figure 2), both of which are open when thevalve 23 is in its closed position, the switch 35 being closed bymovement of the valve to the left in Figure 1 and the switch 36bymovement of the valve to the right in Figure 1. The follow-up action ofthe valve 26 is produced by the movement of the bell-crank lever32.resulting from movement of the piston 25, the arrangement being suchthat the plunger of the valve 26 returns to its intermediate positionwhen a selected gear has been engaged. Thus the selection of any gear bymovement or thelever 29 closes one of the switches 35. or 36, and theengagement of the gear re-opens that switch, the other switch remainingopen throughout the gear changing'operation.

The throttle control device 20' is 'shown' in detail in Figures 3, 4 and5. In those figures, 31 is the main passage in the carburettor bodythrough which the mixture flows to the induction manifold of theengineyand 38 is the throttle valve, which is mounted on a Sp 39 P ingoutwardly'atone end, the projecting end passing through a sleeve screwedinto the carburettor body and itself projecting to form a bearing for aboss carrying an arm 4| connected by a cable 42 to a normal throttlecontrol pedal, and connected also to a return'spring 43 anchored at asuitable point on the engine. Secured to the projecting end of thespindle 38 is another arm 44, and a tension spring 45 is connectedbetween pins46 and 41 on the arms 4| and 44, the spring 45 tending tourge the two arms to relative positions in which the line of action ofthe said spring is radial to the spindle 39, as shown in Figure 3. Thearm 44 carries a pin 48, ofisetwith respect'to the axis of the spindle89, so that'it moves through an arcuate path as the throttle valve 38opens or'closes.

A bracket 49 suitably secured to the carburettor body supports twoco-axial solenoids 50 and the armatures 52 and53 of which carry slottedheads 54 and 55 into'the slots of which the pin 48 projects. When thesolenoids are deenergised, the heads 54 and 55 occupy the positionsshown in Figure 3, in which their slots coincide, and the pin 48 is'treeto move through an angle sufficient to allow the full normal range ofmovement of the throttle valve. The switches 35 and 36 respectively actto close electric circuits including the'solenoids 50 andfil, so thatthe solenoid 50 is energised when an upward gear change is effected, andthe solenoid 5| is energised when a downward gear change is effected. Aswitch 56 (Figure l) controlled by the engagement of its operatingplunger with the rod 21, isheld-intheclosed position when the hand lever29. is in a position 101" selecting'any of the forward gears, but isopened when the hand lever 29 is moved to the neutral or reversepositions, by the operating lunger riding on to a reduced portion 51 ofthe rod, the switch 56 being in series with both the switches 35 and-36,:-so that, when it is open, the closing of these switches does notenergise the solenoids.

.When the solenoid 50 is energised, the armature 52 thereof is drawninto the coil, thus moving the head 54 to the right, so that thelefthand end -of the slot therein acts as a stop to limit the movementof the pin 48 to the left, and so tolimit the openin of the throttlevalve, for example to one eighth of its full opening movement. If thethrottle valve is more than one eighth open, the arm '44 is turned asthe head 54 moves to reduce the throttle opening, the arm 44 beingvturned relative to the arm 4| and tensioning the spring 45, so that theposition of the normal throttle control is unaffected.

When the solenoid 5| is energised, the armature 53 is drawn into thecoil of that solenoid, thus moving the head 55 to the left so that theright hand end of the. slot therein acts as a stop to limit themovementof the pin 48 to the right, and so limits .the closing of the throttle,for example to a .position in which it is threeeighthsopen. The throttlevalveis moved-towards the open position it necessary, with relativemovement of the arms 4| and 44.

v"li'hus each time'the handlever 29 is moved to the. right. to make anupward gear change, the switch 35 .is closed, energising'the solenoid50. The throttle valve 38, is therefore set to a position in which it isnot more than one eighth open, regardless of the position of'thethrottle pedal, and. remains in'that position until the higher gear isengaged and the solenoid 50 de-energised, when, if the throttle pedalhas been kept in a depressed position, the throttle valve reopens to aposition corresponding to the pedal position.

When the hand lever 29 is moved to the left to make a downward gearchange, the switch 36 is closedto energise the solenoid 5|, and thethrottle valve 38, if it is less than three-eighths open, is moved withthe head 55, so that it is at least three-eighths open, regardless ofthe position of the throttle pedal. The head 55 remains in its operativeposition until the lower gear is engaged and the solenoid5|de-energised, allowing the throttle valve to close if the throttle pedalhas been released.

Figure 6 shows a form of throttle control device in which the throttlestops areactuated by suction derived from the suction manifold of theengine, the application or the suction being. controlled electrically,the throttle control beingassociated with gear change mechanism of thesynchro-mesh type in which the gear changes are effected mechanically bymovement of a lever mounted on a rod extending parallel to the steeringcolumn, the rod being moved axially to select the appropriate shift barof the gear-box, and angularly to engage the gears. The throttle controlunit is shown at 60, the electrically operated vacuum control valveattl, and the con- 5 trol switch at 62. A vacuum reservoir is shown at63.

The throttle control unit 60 is shown in detail in Figure 7, the spindleof the throttle valve being shown at 64. The carburettor and throttlevalve are not shown in the drawings. A sector-shaped plate 65 fixedlymounted on the throttle valve spindle 94, and a pin 99 projects from oneside of the plate 65, at a point off-set from the axis of the spindle64, to co-operate with two movable stops 61 and 68. Pivotally attachedto the other side of the plate 95 is one end of a resilient link 99, theother end of which is pivoted to a lever I connected by a cable H to thenormal throttlecontrol. A return spring 12 for urging the throttle valveto the closed position is also connected to the lever 10. The resilientlink 69 comprises inner and outer telescoping members 13 and 14, theinner member 13 having a pair of opposed external shoulders 15 and 16,and the outer member having a pair of opposed internal shoulders I1 andE8, the two pair of shoulders being equally spaced. A pair of sleeves19, urged apart by springs 80 between which is interposed a washer 9i,co-operate with the shoulders to urge the members 13 and 14 to aposition in which the shoulders 15 and 11 are in a common plane and theshoulders 16 and 18 are in another common plane, extension orcompression of the link causing compression of the springs.

The stops 61 and 98 are associated respectively with bellows 02 and 83.The bellows 82 has an inner end plate 90 fixed to a bracket 85, the stop91 being carried by a rod 86 passing through the inner end plate 84 andsecured to the outer end plate 81 of the bellows, and a spring 88 beingincorporated in the bellows to extend it. The bellows 93 has inner andouter end plates 89 and 90 both fixed to a bracket 9i, and a movableintermediate plate 92 carrying a rod 93 slidable in the inner end plate89, the rod 93 carrying the stop 69. The bellows 82, and the chamber 94of the bellows 93 between the outer end plate 89 and the intermediateplate 92 have a common connection to the vacuum control valve 9i, andthe other chamber 95 of the bellows 83 has a separate connection to thevacuum control valve BI. A spring 96 in the chamber 95 urges theintermediate plate 92 outwardly.

The vacuum control valve, which is shown in detail in Figures 8 and 9,comprises a body 91 having an axial bore 98 which is counterbored atboth ends to provide recesses 99 and I00, the recesses being closed byend caps IOI, I02 formed with central openings I 93 and I04 respectivelyleading into chambers I and I06 in the end caps. A pipe ml, connected tothe inlet manifold of the engine, leads into the bore 93, a nonreturnvalve I88 being provided to prevent flow of air into the bore 98 fromthe inlet manifold. Another pipe I09 connects the bore 98 to the vacuumreservoir 63. A pipe I I0 leads from the recess 99 to the chamber 99 inthe bellows 83, and a pipe III leads from the recess I00 to the chamber94 in the bellows 83, and to the bellows 82. Another pipe I I2 leadsfrom the recess 99 to a vacuum cylinder (not shown) for disengaging theclutch of the vehicle. The recess I00 and the chamber I05 are connectedtogether by passages ii 3 (Figure 9). Solenoids H4 and H5 are mountedrespectively on the end caps I 0| and I92, the armatures of thesolenoids carrying respectively valve heads I I6 and H1 located in therecesses 99 and I00. The armaturesare urged inwardly by springs I I8 andH9 respectively to seat the valve heads on the shoulders at the innerends of the recesses so as to close the ends of the bore 98,energisation of the respective solenoids drawing the valve headsoutwardly so that they close respectively the openings I03 and I04 inthe end caps IOI and I02. Air inlet ports I20 are provided in the endcap I02.

When both solenoids are de-energised, both valve heads are in theirinner positions, and the three pipes H0, III and H2 are connected to theatmosphere through the ports I29, so that both stops 51 and 68 arewithdrawn from their oper-' ative positions. When the solenoid H5 isenergised, the recesses 99 and I00 are cut off from the ports I20, andsuction is applied to all three pipes IIB, III and H2. As the suctionacts on both sides of the intermediate plate 92 in the bellows 83, thestop 58 is not affected, but the suction acting in the bellows 92 drawsthe end plate 81 towards the end plate 84, thus moving the stop 61inwardly to reduce the throttle opening to a small value, if it is wideopen, or to limit its opening. Suction is also applied to the clutchvacuum cylinder to disengage the clutch. When the solenoid H4 isenergised, the pipes H0 and II 2 only are connected to suction, so thatthe intermediate plate 92 of the bellows 83 is displaced inwardly toopen the throttle valve or prevent it from closing, and suction isapplied to the clutch vacuum cylinder to hold the clutch disengaged, thebellows 82, and the chamber in the bellows '83, remaining connected tothe atmosphere.

The bellows 82 and 83 may be replaced by cylinders, the stops 61 and 08being secured to pistons slidable in the said cylinders.

Fi ures 10, 11 and 12 show the operating mechanism for the switch theswitch itself, which is of the double pole type, being mounted on thesteering column I2! of the vehicle. The operating plunger 522 of theswitch is operated by cam strips I 23 secured to the gear-change rod524, the cam strips being so positioned on the rod I24 that the plungeris depressed only when a gear is fully engaged. Zhe switch 6?. ismounted on a pipe clip I25 which is clamped onto the steerin column I2I,the pipe clip having secured to it two diametrically opposed ears I129,[2253. A bracket I2? clamped to the gear-change rod I20 carries arocking arm i23, and two tension springs I29, I29 extend between theears Q29 and the arm i253, the springs tending to urge the rod in eitherdirection from a dead-centre position to hold it in a positioncorresponding to full engagement of any gear.

The contacts of the switch which are closed when the operating plunger522 is depressed, are in the circuit of the solenoid lid, which circuitalso includes contacts closed only when the clutch of the vehicle isdisengaged. and its driving member is revolving at a lower speed thanits driven member. The other contacts of the switch which are closedwhen the operating plunger I22 is free, are in the circuit of thesolenoid H5. Therefore, when any gear is engaged and the clutch also isengaged, both circuits are open. The sequence of operations during gearchanging is as follows. When the gear lever is moved to disengage theoperating plunger 22 is released, and the circuit of the solenoid H5 isclosed, causing the throttle stop 9"! to be moved inwardly, thus nearlyclosing the throttle if it is not already closed, and disengaging theclutch. The continued-movement of the gear lever .engages the. freshgear, opening the previously closed contacts of the switch 62, andclosing the contacts thereof in the circuit of the solenoid III. If thedriving member of the clutch is revolving at a lower speed than thedriven member, the circuit of the solenoid H4 is closed, and thethrottle stop 63 is moved inwardly to speed up the engine until thedriving member slightly overruns the driven member, the clutch beingmeanwhile held disengaged. When the driving member begins to overrun,the clutchcontrolled switch is opened, and the solenoid I I4 istle-energised, thus allowing the clutch to engage, and the stop 68 to bewithdrawn.

Figures 13 and 14- show a modified arrangement of the mechanism foroperating the switch 62. The switch is secured to the steering columnI2I by a two-piece clamp I36, and its operating plunger (22 is actuatedby a lever I3I pivoted at I32 on the clamp. he lever lSI carries aroller I33 acting a cam follower, and the gear change rod carries fivecams I34, I35, I35, I31 and I33 so placed t 1st the cams Iii-'l and I35are engaged with the roller when the gear lever is engaged with thethird and fourth gear shift bar, the cams I35 and are engaged with theroller when the gear lever is engaged. with the first and second gearshift bar, and the cam I38 is engaged with the roller when the gearlever is engaged with the reverse gear shift bar. Each cam has a notchsuch as those shown at I39 in Figure 13 to receive the roller when thecorresponding gear is engaged, and the cams are individually adjustableon the rod I24.

Figure 15 shows a modified arrangement for connecting the IiOli8.lthrottle control cable 1| to the throttle valve. The valve spindle 64carries an arm I ll fixed thereto and supporting the pin 58 which(Io-operates with the throttle stops B1 and 68, those stops beingoperated by the bellows 82 and 83 as described with reference to Figure7. The cable H is attached to another arm I4I which is free to turn onthe spindle B4, and is engaged between the two arms of a somewhatU-shapcd leaf spring M2 fixed to the arm I43.

Thus the cable (I is normally able to operate the throttle valve throughthe leaf spring I42, but, if either stop or {it moved to limit thethrottle valve movement, and the normal throttle control is held in aposition to set the throttle to a position outside the limited range,the spring I42 can yield.

Only one stop may be provided, which is rendered operative to set thethrottle valve within a predetermined range for all gear changes, or forchanges in one direction only.

I claim:

1.ln a motor vehicle including an engine, throttle valve means forcontrolling the speed of the engine, a change-speed gearbox throughwhich wheels of the vehicle are driven by the engine, means for engagingand disengaging the various gear ratios of the gearbox, and a frictionclutch including driving and driven members between the engine and thegearbox, throttle control means including a driver operated throttlecontrol member, means connecting said driver operated throttle controlmember to the throttle valve, a resilient connection in said connect-5112 means enabling the throttle valve to move independently of thedriver-operated throttle control member, a stop contacting member movingwith the throttle valve, two movable stops cooperating with saidstop-contacting member, one of said stops having an operativeposition inwhich it'limits the opening of the throttle valve and the other of saidstops having an operative position in which it limits the closing ofsaid throttle valve, stop actuating means for moving the first-mentionedstop to its operative position, separate stop actuating means for movingthe second-mentioned stop to its operative position, said first stopactuating means being actuated by the gear engaging and disengaging meanto disengage any gear ratio, said second stop actuating means beingactuated by movement of the gear engaging and disengaging means toengage a gear-ratio, and being subsequently returned from its operativeposition upon the attainment of synchronism between the driving anddriven members of the friction clutch.

2. In a motor vehicle including an engine, throttle valve means forcontrolling the speed of the engine, a change speed gear box throughwhich wheels of the vehicle are driven by the engine, and means forengaging and disengaging the various gear ratios of the gearbox,throttle control means including a driver-operated throttle controlmember, means connecting said driver-operated throttle control member tothe throttle valve, a resilient connection in said connecting meansenabling the throttle valve to move independently of the driver-operatedthrottle control member, a stop-contacting member moving with thethrottle valve, a movable stop co-operating' with said stop-contactingmember, a solenoid, an armature in said solenoid carrying said stop, asource of electric current, switch means for controlling the connectionof said solenoid to said electric current source, said solenoid, whenenergized, moving the stop from a position in which it allows thethrottle valve to move through its full range to a position in which itrestricts the throttle valve movement to a limited range, and switchoperating means actuated by the gear engaging and disengaging means toclose the switch when the said means is operated to disengage any gearratio.

3. In a motor vehicle including an engine, throttle valve means forcontrolling the speed of the engine, a change-speed gearbox throughwhich wheels of the vehicle are driven by the engine, and means forengaging and disengaging the various gear ratios of the gearbox,throttle control means including a driver-operated throttle controlmember, means connecting said driver-operated throttle control member tothe throttle valve, a resilient connection in said connecting meansenabling the throttle valve to move independently of the driver-operatedthrottle control member, a stop-contacting member moving with thethrottle valve, first and second movable stops co-operating with saidstop-contacting member, said first stop having an operative position inwhich it limits the opening of the throttle valve and said second stophaving an operative position in which it limits the closing of thethrottle valve, a. first solenoid operatively connected to said firststop, a second solenoid operatively connected to said second stop, asource of electric current, first switch means controlling theconnection of said first solenoid to the current source, second switchmeans controlling the connection of said second solenoid to the currentsource, and means operated by the gear engaging and disengaging meansfor selectively operating said first and second switch meansrespectively when said gear engaging and disengaging means is moved toeffect a. change to a higher and a lower gear ratio.

4. In a motor vehicle including an engine, throttle valve means forcontrolling the speed of the engine, a change-speed gear box throughwhich wheels of the vehicle are driven by the engine, means for engagingand disengaging the various gear ratios of the gearbox, and a frictionclutch including driving and driven members interposed between theengine and the gearbox, throttle control means including adriver-operated throttle control member, means connecting saiddriver-operated throttle control member to the throttle valve, aresilient connection in said connecting means enabling the throttlevalve to move independently of the driver-operated throttle controlmember, a stop-contacting member moving with the throttle valve, firstand second movable stops co-operating with said stopcontacting member,said first stop having an operative position in which it limits theopening of the throttle valve and said second stop having an operativeposition in which it limits the closing of the throttle valve, a firstfluid actuator operatively connected to said first stop to move it toits operative position, a second fluid actuator operatively connected tosaid second stop to move it to its operative position, a source ofworking fluid, valve means controlling the supply of working fluid fromsaid source to said first and second fluid actuators and valve controlmeans responsive to movement of said gear engaging and disengaging meansand to synchronism between said driving and driven clutch members, saidvalve control means controlling the valve means to effect operation ofthe first fluid actuator when the gear engaging and disengaging means ismoved to the neutral position, to effect operation of the second fluidactuator when the gear engaging and disengaging means is moved to engagea gear ratio, and to return said second actuator to its inoperativeposition when the driving and driven members of the friction clutch aresynchronized.

5. In a motor vehicle including an engine, throttle valve means forcontrolling the speed of the engine, a change-speed gear box throughwhich wheels of the vehicle are driven by the engine, means for engagingand disengaging the various gear ratios of the gearbox, and a frictionclutch including driving and driven members interposed between theengine and the gearbox,

throttle control means including a driver-operated throttle controlmember, means connecting said driver-operated throttle control member tothe throttle valve, a resilient connection in said connecting meansenabling the throttle valve to move independently of the driver-operatedthrottle control member, a stop-contacting member moving with thethrottle valve, first and second movable stops co-operating with saidstop-contacting member, said first stop having an operative position inwhich it limits the opening of the throttle valve and said second stophaving an operative position in which it limits the closing of thethrottle valve, a first fluid actuator operatively connected to saidfirst stop to move it to its operative position, a second fluid actuatoroperatively connected to said second stop to move it to its operativeposition, a source of working fluid, valve means controlling the supplyof working fluid from said source to said first and second fluidactuators, solenoid means operating said valve means, a source ofelectric current, switch means operated by the gear engaging anddisengaging means, and

switch means operated by the clutch, the switch means operated by thegear engaging and disengaging means operating the valve means to efiectoperation of the first fluid actuator when the gear selecting means ismoved to the neutral position and to effect operation of the secondfluid actuator when the gear engaging and disengaging means is moved toengage a gear ratio, and the switch means operated by the clutchoperating the valve means to return the second actuator to itsinoperative position when the driving and driven members of the clutchare synchronized.

6. In a motor vehicle including an engine, throttle valve means forcontrolling the speed of the engine, a change speed gearbox throughwhich wheels of the vehicle are driven by the engine, manually operatedmeans for engaging and disengaging the various gear ratios of thegearbox, and a friction clutch including driving and driven membersinterposed between the engine and the gearbox, throttle control meansincluding a driver operated throttle control member, means connectingsaid driver operated throttle control member to the throttle valve, aresilient connection in said connecting means enabling the throttlevalve to move independently of the driver-operated throttle controlmember, a stop-contacting member moving with the throttle valve, firstand second stops co-operating with said stop-contacting member, firstand second fluid actuators, means connecting said first and second fluidactuators respectively to said first and second stops, a source ofworking fluid, valve means controlling the supply of working fluid fromsaid source to said fluid actuators, solenoid means operating said valvemeans, a source of electric current, switch means operated by themanually operated gear engaging and disengaging means, and switch meansoperated by the clutch, the switch means operated by the manuallyoperated gear engaging and disengaging means operating the valve means,when the said gear engaging and disengaging means is moved to theneutral position, to effect operation of the first fluid actuator andthereby position the first stop to limit the opening of the throttlevalve, and operating the said valve means when the said gear engagingand disengaging means is moved to engage a gear ratio, to effectoperation of the second fluid actuator and thereby position the secondstop to limit closing of the throttle valve, and the switch meansoperated by the clutch operating the valve means when the speeds of thedriving and driven clutch members are synchronized, to return the secondactuator to its inoperative position.

SYDNEY MACDONALD PARKER.

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